Why can you use cross products to solve the proportion StartFraction 18 over 5 EndFraction = StartFraction x over 100 EndFraction for x?

Answers

Answer 1

9514 1404 393

Answer:

  it is application of the multiplication property of equality

Step-by-step explanation:

You can use "cross products" to solve any proportion. What looks like a "cross product" is just application of the multiplication property of equality. That property says the variable value is unchanged if both sides of the equation are multiplied by the same value.

For your fraction, the "cross product" is what you get when you multiply both sides of the equation by 500.

  [tex]\dfrac{18}{5}=\dfrac{x}{100}\qquad\text{given}\\\\\dfrac{18\cdot5\cdot100}{5}=\dfrac{x\cdot5\cdot100}{100}\qquad\text{multiply by $5\cdot100$}\\\\18\cdot100=5\cdot x\qquad\text{cancel common factors; looks like cross product}[/tex]

__

Note that the next step here is to divide by the x-coefficient, the 5 that was in the left-side denominator.

  [tex]\dfrac{18\cdot100}{5}=x\qquad\text{divide by 5}[/tex]

Please also note that this is exactly the same result you would get by multiplying the original equation by the original denominator of x.


Related Questions

You deposit $5000 in an account earning 8% interest compounded monthly. How much will you have in the account in 5 years?

Answers

Answer:

A = $ 7,449.23

A = P + I where

P (principal) = $ 5,000.00

I (interest) = $ 2,449.23

Step-by-step explanation:

Compound Interest Equation

A = P(1 + r/n)^nt

Where:

A = Accrued Amount (principal + interest)

P = Principal Amount

I = Interest Amount

R = Annual Nominal Interest Rate in percent

r = Annual Nominal Interest Rate as a decimal

r = R/100

t = Time Involved in years, 0.5 years is calculated as 6 months, etc.

n = number of compounding periods per unit t; at the END of each period

Compound Interest Formulas and Calculations:

Calculate Accrued Amount (Principal + Interest)

A = P(1 + r/n)^nt

Calculate Principal Amount, solve for P

P = A / (1 + r/n)^nt

Calculate rate of interest in decimal, solve for r

r = n[(A/P)(^1/nt) - 1]

Calculate rate of interest in percent

R = r * 100

Calculate time, solve for t

t = ln(A/P) / n[ln(1 + r/n)] = [ ln(A) - ln(P) ] / n[ln(1 + r/n)]

Formulas where n = 1 (compounded once per period or unit t)

Calculate Accrued Amount (Principal + Interest)

A = P(1 + r)^t

Calculate Principal Amount, solve for P

P = A / (1 + r)^t

Calculate rate of interest in decimal, solve for r

r = (A/P)1/t - 1

Calculate rate of interest in percent

R = r * 100

Calculate time, solve for t

t = t = ln(A/P) / ln(1 + r) = [ ln(A) - ln(P) ] / ln(1 + r)

Continuous Compounding Formulas (n → ∞)

Calculate Accrued Amount (Principal + Interest)

A = Pe^rt

Calculate Principal Amount, solve for P

P = A / ert

Calculate rate of interest in decimal, solve for r

r = ln(A/P) / t

Calculate rate of interest in percent

R = r * 100

Calculate time, solve for t

t = ln(A/P) / r

-y=-6x-3
write in the slope-intercept form please!: y=mx+b
please show work too!

Answers

Answer:

y = 6x + 3

Step-by-step explanation:

Since you can't have a negative y in a y = mx + b equation you have to make it postive. You also have to do everything you do on one side to the other. To do this you have to multiply everything by -1. This will make everything positive b/c it cancels out the other negative. (Two negatives equals a positive) You should be left with y = 6x + 3. The -1 cancelled the -y, -6x, and -3 so you add 3 instead of subtract it.

y = 6x + 3

Glven: -7x < -21. Choose the solution set.​

Answers

Answer:

x > 3

Step-by-step explanation:

-7x < -21

Divide each side by -7, remembering to flip the inequality

-7x/-7 > -21/-7

x > 3

Answer:

x > 3

Step-by-step explanation:

Get the variable (x) by itself. Divide both sides by -7. Since a negative/ negative = positive, the 3 is positive.  When you multiply or divide by a negative, the inequality sign flips. I hope this helped.

How do I get the answers down below? Could anyone help me? I will give brainliest and 25 points :)))
In the figure below, the horizontal lines are parallel. Find the measure of the labeled angles: 2y+2 and 4y-2

THE ANSWERS ARE:
(2y+2)=62degrees
(4y-2)=118degrees
y=30

Answers

Answer:

Step-by-step explanation:

The angles that you have shown are called same side exterior angles.

All same side exterior angles add to 180 degrees

Since we know this, we can make the following equation:

2y+2+4y-2=180

6y=180

y=30

To get each angle you can plug in y:

2*30+2=62

4*30-2=118

I hope this helps :)

Emily can ride her scooter 18 miles in 50 minutes.

c. What is her unit rate in miles per hour?

Answers

Answer:

22.5 miles per hour (rounded answer)

Step-by-step explanation:

This is a fraction equal to

18 miles ÷ 0.8 hours

We want a unit rate where

1 is in the denominator,

so we divide top and bottom by 0.8

18 miles ÷ 0.8

0.8 hours ÷ 0.8

=  

22.5 miles

1 hour

=  

22.5 miles

hour

= 22.5 miles per hour

Answer:

there is no miles per hour because she wasn't riding for an hour

Zachary is planning to send a video game to each of his two brothers. If he buys the same game for both
brothers and pays $6.25 to ship each game, how much can he spend on each game without spending
more than $100? Enter and solve an inequality for this situation. Let v be the cost of one video game.
The inequality is .
Zachary can spend no more than $
on each video game.

Answers

Answer:  The required amount of money spent on each of the two video games is less than or equal to 45.25.

Step-by-step explanation:  Given that Zachary is planning to send a video game to each of his two brothers. He buys the same game for both brothers and pays $4.75 to ship each game.

We are to write and solve an inequality find the amount spent on each game without spending more than $100.

Let $x be the amount that is spent on each of the two video games.

Then, according to the given information, the inequality can be written and solved as follows :

Thus, the required amount of money spent on each of the two video games is less than or equal to 45.25.

it had to dell with Finding the Slope from Points​

Answers

Answer:

Step One: Identify two points on the line.

Step Two: Select one to be (x1, y1) and the other to be (x2, y2).

Step Three: Use the slope equation to calculate slope.

Step-by-step explanation:

from google

What additional information could
be used to prove the triangles
similar using AA-?

Answers

Answer:

.

Step-by-step explanation:

A microscope is set so it makes an object appear 6 × 10 2times larger than its actual size. A virus has a diameter of 2 × 10 -7meters. How large will the diameter of the virus appear when it's viewed under the microscope?

Answers

Answer:

The diameter of the virus will appear as 1.2 × 10⁻⁴ meters when viewed under the microscope

Step-by-step explanation:

From the question,

A microscope is set so it makes an object appear 6 × 10² times larger than its actual size. That is, when an object is viewed with the aid of the microscope, the object will be 6 × 10² times larger than its actual size.

Now, to determine how large the diameter of a virus that has a diameter of 2 × 10 ⁻⁷ meters will appear when viewed under the microscope, we will multiply the diameter of the virus by  6 × 10².

That is, 2 × 10 ⁻⁷meters × 6 × 10² = 1.2 × 10⁻⁴ meters

Hence, the diameter of the virus will appear as 1.2 × 10⁻⁴ meters when viewed under the microscope.

Solve the equation.

8 – 2x = –8x + 14

Will give Brainliest if explained.

Answers

Answer:

x = 1/3

Step-by-step explanation:

Move all terms containing x to the left side of the equation.

8+6x=10

Move all terms not containing x to the right side of the equation

6x=2

Divide each term by 6 and simplify.

Exact Form:

x=1/3

Decimal Form:

x=0.3333333333

Hope this helps!

Who wants to help with 7th grade math? 10 points (i put in 20 points)

Answers

Answer:

2 apples = .24 kilograms

12 apples = 1.44 kilograms

Step-by-step explanation:

If 5 apples all weigh The same amount. Let x represent one apples weight

5x = 0.60

divide by 5

one apple weighs .12 kilograms

then multiply by the number of apples. So 2 apples is .24

and 12 apples is 1.44

P(An B)
P(AB) =
P(B)
Freshmen
Sophomores
Juniors
Seniors
1
4
2.
Boys
3
9
7
6
5
Girls
P(Boy|Senior) =
ON
?

Answers

The probability of P(Boy/Senior) is 2/37.

Given that, the total number of students=37 and the number of senior boys=2.

P(A|B)=P(A ∩ B)/P(B).

We need to find P(Boy/Senior).

What is P(A∩B)?

P(A ∩ B) indicates the probability of A and B, or, the probability of A intersection B means the likelihood of two events simultaneously, i.e. the probability of happening two events at the same time.

Now, P(Boy/Senior)=2/37.

Therefore, the probability of P(Boy/Senior) is 2/37.

To learn more about the probability of an event visit:

https://brainly.com/question/17089724.

#SPJ2

Answer:

2/7

Step-by-step explanation:

2 seniors / 7 seniors in total

GUYS PLEASE HELP LIKE I MEAN IT CAN SOMEONE TELL ME THE ANSWER WITH AN EXPLANATION

Answers

Answer:

I think its 183 1/3

It's what I figured out & the other answer says the same.

Step-by-step explanation:

You like TommyInnit, too? Poggers! <3

Answer:

183 1/3

Step-by-step explanation:

I'm assuming that x and y are directly proportional.

So anyways:

5.5 divided by 3/4 is 7 1/3.

Because this is directly proportianol, you'll also have to mutiply y by 7 1/3.

So: 25 times 7 1/3 equal to 183 1/3

Hope this helps!

what is the answer to 805÷24 plz tell me

Answers

Answer:

33.5416666667

Step-by-step explanation:

805/24 math problems division = 33.5416666667. Therefore 33.5416666667 to 2 decimal places= 33.54

805/24 divided by 2 » (805/24) ÷ 2 » 33.5416666667 ÷ 2 = 16.7708333333 . Check 805/24 long division below

Nicole is making 1,000 bows for people who donate to the library book sale. She needs a piece of ribbon that is o.75 meters long for each bow. How many meters of ribbon does Nicole need to make for the bows? Explain how to find the answer.

Answers

Answer:

750 meters

Step-by-step explanation:

In order to calculate the total amount of ribbon that she needs, we need to multiply the amount of ribbon that each bow needs by the total number of bows that need to be made. Since we are given both of these values we simply multiply and solve for x which is the total amount of ribbon that Nicole needs.

1000 * 0.75 = 750 meters

Therefore, Nicole needs a total of 750 meters to make all of the needed bows.

You have eight more dogs than cats. You have 2 fewer chickens than dogs. You have three fewer guinea pigs than cats. If you have a total of 59 pets, write an equation that would help you find how many of each pet you have. Describe what the variable represents (Let __ represent...).

Answers

Answer:

read the answers below.

Step-by-step explanation:

d = dog

d = c + 8

ch = chickens

ch = d -2

gp = guinia pigs

gp = c - 3

d + c + ch + gp = 59

gp = c- 3

gp = d -8 - 3

gp = d - 11

d + d-8 + d - 2 + d-11 = 59

4d -8 - 2 - 11 = 59

4d - 21 = 59

4d - 21 + 21 = 59 + 21

4d = 80

4d/4 = 80/4

d = 20

========

c = d - 8

c = 20 - 8

c = 12

========

ch = d - 2

ch = 20 - 2

ch = 18

=========

gp = d - 11

gp = 20 - 11

gp = 9

Which represents the solution up above ^^^^^^^^^^

Answers

Answer:

-2x <= x < 3

Step-by-step explanation:

Subtract 4 from all sections to isolate the x and then divide everything by 3 to make there be only 1 x

3x+3(x+y) please help

Answers

Answer:

6x + 3y

Step-by-step explanation:

distribute

3x + 3x + 3y

Combine like terms

6x + 3y

theres ur answer

Find the balance in the account.
$3,800 principal earning 2%, compounded annually, after 7 years

Answers

Answer:

A = $4360.515918 which rounded to the nearest penny is $4360.52

Step-by-step explanation:

likewise 133 degree is equal to 87 degree in the second at what temperature will both thermometer read the same​

Answers

Here's your answer..........

Math inequality help

Answers

This is how it will look

Jodie bought a refrigerator on sale for 35% off the original price, for $97. What was the price of the refrigerator before the sale?
I need help

Answers

Answer:

$149

Step-by-step explanation:

As it is 35% off, $97 is therefore 65% of the full price [because 100 -35 = 65].

You can then divide 97 by 65 [1.49 to 2 d.p] to get 1% of the full price. 100% is the full price so we multiply 1.49 by 100 and the result of that is 149.

n/56 divided by 3/24

Answers

Answer:

n/56 divided by 3/24 would be 1/7n

Step-by-step explanation:

what he/she said :’)

I NEED HELP PLS HELP ME!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Answers

420 * 0.15 = 63
There are 63 tickets sold to children

Answer:

x=69

Step-by-step explanation:

15/100=x/460

=>100x=15×460 (cross multiplication)

=>100x=6900

x=69 (divide both side by 100)

Note:if you find my answer helpful. Please mark me as brainliest

The IQ scores of the middle 50% of a population can be written as the one above
Where x is a person’s IQ. Solve the inequality to find the IQ scores for the middle 50% of the population.

Answers

Answer:

90≤x≤110

Step-by-step explanation:

Given two inequality |x-100/15|≤2/3

The modulus value can be negative or positive

For the postive value. x-100/15≤2/3

Cross multiply

3(x-100) ≤30

3x-300≤30

3x≤330

x≤110

For the negative value;

-(x-100)/15≤2/3

100-x/15≤2/3

3(100-x) ≤30

300-3x≤30

-3x≤-270

x≥90

90≤x

Combining both inequalities.

90≤x≤110

Giving BRAINLIEST Select the table that represents a linear function. (Graph them if necessary.)

A.
x 0 1 2 3
y 0 2 5 8

B.
x 0 1 2 3
y 8 6 7 5

C.
x 0 1 2 3
y 10 9 7 4

D.
x 0 1 2 3
y 11 8 5 2

Answers

answer is a because while doing it in graph it seems a straight line

Bella wants to save for a vacation in three years and this vacation costs $2300. She deposits $2000 into a bank earning 5% interest compounded monthly. How much money does Bella have after 3 years?

Answers

Answer:

$2,323.2

Step-by-step explanation:

A = P(1 + r/n)^nt

Where,

A = future value = ?

P = present value = 2,000

r = interest rate = 5% = 0.05

n = number of periods = 12

t = time = 3 years

A = P(1 + r/n)^nt

= 2,000(1 + 0.05/12)^12*3

= 2,000( 1 + 0.00417)^36

= 2,000( 1.00417)^36

= 2,000(1.1616)

= 2,323.2

A = $2,323.2

anyone know how to do this one??

Answers

Answer:

y=1/3x+5

Step-by-step explanation:

y=1/3x+5 have a nice day hope you get it right

4 2/3 miles in 3/4 hour
4/23 divided by 3/4 ?

NEED FAST ANSWERS !

Answers

Answer:

= 12 miles per hour

Step-by-step explanation:

This is a fraction equal to

30 miles ÷ 2.5 hours

We want a unit rate where

1 is in the denominator,

so we divide top and bottom by 2.5

30 miles ÷ 2.5

2.5 hours ÷ 2.5

=  

12 miles

1 hour

=  

12 miles

hour

= 12 miles per hour

if the length of a flag is 18 inches and the width is 12 inches what is the area

Answers

Answer:

18 by 12 is 216

Answer:

216

Step-by-step explanation:

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